MDI-QKD: Improving Asymmetric Models with Advantage Distillation

Measurement-device-independent quantum key distribution (MDI-QKD) completely closes the security loopholes caused by imperfections of the devices at the detection terminals. Although the symmetric MDI-QKD model is widely used in simulations and experiments, this scenario is far from the reality of quantum networks, where the channels connecting each user have varying levels of losses. To accommodate this feature, an asymmetric MDI-QKD model is proposed. One important research direction is how to improve the performance of asymmetric MDI-QKD. In this work, a step called advantage distillation (AD) can further improve the performance of asymmetric MDI-QKD without changing the original key distribution process. Simulation results show that the AD method can improve the secret key rate and transmission distance. Therefore, this scheme will greatly promote the development of future MDI-QKD networks.